Herbert Frey, 2011. "Previously unknown large impact basins on the Moon: Implications for lunar stratigraphy", Recent Advances and Current Research Issues in Lunar Stratigraphy, William A. Ambrose, David A. Williams
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Lunar topographic and model crustal thickness data provide evidence for large basins on the Moon not previously recognized by photogeologic mapping. The number of these basins larger than 300 km diameter suggests that the total population may be 2–3 times greater than previously thought. Some previously proposed named basins have little to no basin-like topographic character; most of those that do also have pronounced crustal thickness signatures in the form of circular thin areas (CTAs). There also exist CTAs that lack a pronounced quasi-circular depression (QCD) signature in the available topographic data. Newly recognized candidate basins contribute significantly to a total population in which there are more large basins on the lunar farside than on the nearside. The North Pole region appears remarkably devoid of large basins, with only three larger than 300 km diameter and only one at >70°N. Disruption of the topographic and/or crustal thickness structure can be used to establish overlap relationships between QCDs and CTAs and thus relative ages (and a relative local stratigraphy) for those features not visible in images. If large basins have the ability to significantly modify the surface out to twice their diameter, there are likely no parts of the Moon that remain unaffected by the total population shown here. If such effects extend out to only 1.5 basin diameters, there may be 1.8 million km2 of lunar surface where rocks predating most basin formation may still exist. The early history of the Moon likely involved much greater large-diameter impact cratering than previously thought, and therefore much greater global mixing and redistribution of surface materials. Early lunar stratigraphy is likely far more complex than previously appreciated.